Field of the Invention
The present disclosure relates to an organic light emitting display device and a method of manufacturing the same, and more particularly, to an organic light emitting display device and a method of manufacturing the organic light emitting display device capable of minimizing a voltage drop in a cathode and also securing a high opening ratio.
Description of the Related Art
An organic light emitting display device (OLED) is a self-light emitting display device that does not need a separate light source unlike a liquid crystal display device. Thus, the organic light emitting display device can be manufactured into a lightweight and thin form. Further, the organic light emitting display device is advantageous in terms of power consumption since it is driven with a low voltage. Also, the organic light emitting display device has excellent color expression ability, a high response speed, a wide viewing angle, and a high contrast ratio (CR). Therefore, the organic light emitting display device has been researched as a next-generation display device.
In the case of a top-emission organic light emitting display device, a transparent or semi-transmissive electrode is used as a cathode in order to upwardly emit light emitted from an organic light emitting layer. When a transparent or semi-transmissive electrode is used as a cathode, the cathode is formed to have a small thickness in order to improve transmittance. A reduction in thickness of the cathode causes an increase in electrical resistance of the cathode electrode. Thus, in the case of a large-area organic light emitting display device, as a distance from a voltage supply pad unit is increased, a voltage drop is further increased, which may cause a problem in non-uniformity in luminance of the organic light emitting display device.
In order to minimize a voltage drop, a method of using a separate auxiliary electrode has been used. FIG. 1 is a schematic cross-sectional view of an organic light emitting display device including an auxiliary electrode according to the related art.
Referring to FIG. 1, an organic light emitting display device 100 according to the related art includes a flattening layer 140, a first anode 150, a second anode 152, an auxiliary electrode 154, a first organic light emitting layer 160, a second organic light emitting layer 162, an organic material layer 164, a first bank 170, a second bank 172, a partition wall 174, a first cathode 190, a second cathode 192, and a conductor layer 194.
Herein, the first anode 150, the second anode 152, and the auxiliary electrode 154 are formed of the same material in concurrent processes; the first organic light emitting layer 160, the second organic light emitting layer 162, and the organic material layer 164 are formed of the same material in concurrent processes; and the first cathode 190, the second cathode 192, and the conductor 194 are also formed of the same material in concurrent processes.
In the organic light emitting display device 100 illustrated in FIG. 1, the auxiliary electrode 154 electrically connected with the first cathode 190 and the second cathode 192 minimizes a voltage drop and thus improves the non-uniformity in luminance of the organic light emitting display device 100.
However, in the organic light emitting display device 100 illustrated in FIG. 1, it is necessary to dispose the partition wall 174 for insulating the first organic light emitting layer 160 from the second organic light emitting layer 162 on the auxiliary electrode 154. Thus, it is necessary to secure a predetermined distance w1 for disposing the partition wall 174 between the first bank 170 and the second bank 172.
The predetermined distance w1 between the first bank 170 and the second bank 172 needs to be secured but it does not have an area for light emission. Therefore, if the auxiliary electrode 154 and the partition wall 174 are formed in an organic light emitting display device having the same area as the organic light emitting display device 100 illustrated in FIG. 1, an emission region is reduced and an opening ratio of the organic light emitting display device is decreased.
Accordingly, there has been a continuous demand for new technology capable of suppressing a voltage drop and also minimizing a decrease in an opening ratio of an organic light emitting display device.